JP4019659B2 - Image recording position adjustment method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image recording position adjusting method, and more particularly to an image recording apparatus that mounts a plurality of recording heads and records an image by reciprocating scanning of the plurality of recording heads. The present invention relates to an image recording position adjustment method for correcting an image shift due to a position shift.
[0002]
[Prior art]
The heads arranged in parallel on the carriage are ruled lines printed from the print position between the heads and the deviation that occurs in the head mounting angle with respect to the scanning direction of the carriage due to the mechanical mounting error at the mounting position and mounting posture. Cause a tilt. Also, an image is recorded by the recording head by reciprocating scanning of the carriage. There are cases where an image is recorded only by forward scanning and images are recorded by both forward scanning and backward scanning, but both forward scanning and backward scanning are performed. When recording an image, the recording position of the image is shifted due to an error of a motor or a mechanism for scanning the carriage between the recording position of the forward path and the recording position of the backward path.
[0003]
Therefore, in order to correct the print position, an electrical delay is appropriately given to the print signal applied to the head to cancel the error due to the mechanical attachment or the print characteristic difference between the heads. It is possible to correct the position.
[0004]
At this time, in order to determine an appropriate amount of electrical delay, visual detection or automatic detection by optical detection means is performed using a test pattern printed by shifting the electrical delay by a predetermined amount, and the pattern is included in the pattern. By detecting the shift amount of the parallel pattern and the average density of the pattern, it is possible to appropriately correct the printing position.
[0005]
A deviation amount (color registration deviation) between the print heads in the forward path or the return path occurs only between the heads. Therefore, a color color print head (cyan) arranged in parallel with a reference color (for example, black) for detection. , Magenta, yellow) may be printed, and the pattern is a combination of black and cyan, black and magenta, and black and yellow.
[0006]
On the other hand, since the deviation between the forward path and the backward path also occurs with a single head, conventionally, in order to detect the deviation between the forward path and the backward path (hereinafter referred to as a reciprocal deviation), the difference between the forward path and the backward path with the same head is represented by a parallel pattern. Since it was detected by overlapping, the printed pattern was a monochrome pattern of black, cyan, magenta, and yellow, respectively.
[0007]
[Problems to be solved by the invention]
When the reciprocation detection pattern is printed in a single color, especially when trying to automatically detect the density of the pattern by the optical detection means, the optical detection means has spectral characteristics, so the sensitivity of cyan and yellow is This is not sufficient, and it is difficult to detect the density difference of the monochromatic pattern, and it is necessary to prepare light sources having different spectral characteristics.
[0008]
In addition, due to the configuration of the pattern, the parallel pattern deviates by a predetermined amount from the appropriate value, so that a gap occurs in the pattern and the average density decreases, and this density difference can be detected. (Parallel bars) will overlap. A color with a lower density (lower sensitivity) has a higher tendency to increase the density of the overlapped portion, so that the density improvement in the overlapped portion and the generated gap is offset to make detection of the average density more difficult.
[0009]
Also, since the monochromatic pattern has a low density absolute value, that is, a high reflectance, if the illuminance of the light source is improved to increase the density difference, the output of the light receiving element of the optical detection means will be saturated. I couldn't raise it either.
[0010]
  The present invention has been made to solve the above problems,Based on the block with the highest average density among the blocks with different inclinations relative to the paper transport direction,An object of the present invention is to provide an image recording position adjusting method capable of accurately correcting the recording position of the recording head.
[0011]
[Means for Solving the Problems]
  In order to achieve the above object, the invention of claim 1Each comprising a plurality of nozzles arranged along each of a scanning direction and a predetermined direction intersecting the scanning direction;On the recording mediumIn the scanning directionRecord color images by reciprocating scanningEach recording colorIs differentpluralAn image recording position adjusting method for adjusting each recording position of a recording head, wherein a recording head of a predetermined color among the plurality of recording heads is defined as a reference recording head,A block consisting of a plurality of first reference parallel bars having the same inclination angle with respect to the predetermined direction on the recording medium using a plurality of nozzles positioned upstream of the predetermined direction of the reference recording head, A plurality of blocks are recorded along the predetermined direction so that the inclination angles of the first reference parallel bars of each block are different, and the plurality of nozzles positioned downstream of the reference recording head in the predetermined direction are used. Recording a second reference parallel bar between the first reference parallel bars of each block on the recording medium, wherein the inclination angle is the same as the inclination angle of the first reference parallel bar in each block; Detecting the average density of each block including the first reference parallel bar and the second reference parallel bar, and setting the inclination angle of the bar of the block having the highest average density as the amount of inclination of the reference recording head; According Of the reference recording headIt is characterized by adjusting the recording position.
[0012]
  According to the invention of claim 1,The plurality of recording heads having different recording colors each include a plurality of nozzles arranged along a scanning direction and a predetermined direction intersecting the scanning direction, and reciprocally scans the recording medium in the scanning direction. To record a color image. First, a recording head having a predetermined color among the plurality of recording heads is determined as a reference recording head. A block composed of a plurality of first reference parallel bars each having a same inclination angle with respect to the predetermined direction on the recording medium, using a plurality of nozzles positioned upstream of the predetermined direction of the reference recording head. A plurality of blocks are recorded along a predetermined direction so that the inclination angles of the first reference parallel bars of the blocks are different. Furthermore, a plurality of nozzles positioned downstream in the predetermined direction of the reference recording head are used, and a second reference whose inclination angle is the same as the inclination angle of the first reference parallel bar in each block on the recording medium. Parallel bars are recorded between the first reference parallel bars of each block. Next, the average density of each block including the first reference parallel bar and the second reference parallel bar is detected, and the inclination angle of the bar having the highest average density is set as the inclination amount of the reference recording head. As a result, the recording position of the reference recording head is adjusted. Therefore, since the amount of inclination of the reference recording head is adjusted by the average density of each block including the first reference parallel bar and the second reference parallel bar recorded by the reference recording head, the recording position of the reference recording head is adjusted. Correction can be performed accurately.
[0013]
  According to the second aspect of the present invention, when the reference recording head is a black recording head for recording a black image, the reference parallel bar becomes black.InTo be recordedStandardSince parallel bars are recorded on the recording medium, GroupSemi-recording headToMore recordedStandardOf parallel barsOf inclination with respect to a given directionDeviation can be detected.Accordingly, the recording position of the inclination of the black recording head with respect to the predetermined direction can be adjusted.The density difference can be detected by an optical detection means or the like.
  According to a third aspect of the invention, after adjusting the recording position of the reference recording head, a plurality of third references arranged in the scanning direction on the recording medium using the reference recording head. A block consisting of parallel bars is recorded in a plurality of blocks along the predetermined direction so that the position of the third reference parallel bar of each block is shifted by a predetermined dot in the scanning direction, and is recorded separately from the reference recording head. A first parallel bar is recorded on the recording medium using a head between the plurality of third reference parallel bars of each block, and includes the third reference parallel bar and the first parallel bar. By detecting the average density of each block and setting the amount of dot shift of the block with the highest average density as the correction amount of the other recording head, the recording position of the recording head different from the reference recording head is adjusted. It can be.
  According to the fourth aspect of the present invention, after adjusting the recording position of the reference recording head, the reference recording head is used to move a plurality of reference parallel bars onto the recording medium during forward scanning or backward scanning. A plurality of parallel bars are recorded on the recording medium using the recording head different from the reference recording head or the reference recording head during forward and backward scanning, and the positions of the reference parallel bar and the parallel bar are recorded. Based on the relationship, the recording positions of the plurality of recording heads during forward and backward scanning can be adjusted.
  Further, according to the invention described in claim 5, after adjusting the recording position of a recording head different from the reference recording head and the reference recording head, a plurality of recording media are formed on the recording medium using the reference recording head. A reference parallel bar is recorded during forward scanning or backward scanning, and a plurality of parallel bars are recorded on the recording medium using the recording head different from the reference recording head or the reference recording head during forward and backward scanning. The recording positions of the plurality of recording heads during forward and backward scanning can be adjusted based on the positional relationship between the reference parallel bar and the parallel bar.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 shows a schematic configuration of a color printer 10 according to an embodiment of the present invention. As shown in FIG. 1, the color printer 10 is provided with a rod 14 on a housing 12, and a carriage 16 that moves along the rod 14. On the carriage 16, color print heads 18 (K print head 18K, C print head 18C, M print head 18M, and Y print head 18Y) for recording colors corresponding to the colors of CMYK are detachably mounted. Recording in the main scanning direction is performed by moving 16 along the rod 14.
[0016]
Further, the color printer 10 is provided with a platen 20 on which the paper P as a printing medium is placed, and the paper P moves on the platen 20 in a direction intersecting the main scanning direction of the carriage 16. Thus, recording in the sub-scanning direction is performed.
[0017]
That is, an image is formed in the main scanning direction by discharging the ink of each color of the color print head 18 mounted on the carriage 16 while scanning the carriage 16 along the rod 14 in the main scanning direction. Note that an image is formed in the entire or a partial area of the recording area formed on the paper P on the platen 20 by the nozzle row length (sub scanning direction) of the color print head 18 and the scanning length of the carriage 16. Then, paper P is fed by an amount corresponding to the length of the image formed in the sub-scanning direction, image formation is performed again in the main scanning direction, and image formation in the main scanning direction and paper feeding in the sub-scanning direction are repeated. Thus, an image is formed on the entire surface of the paper P. Further, as shown in FIGS. 1 and 2, each color print head 18 is arranged in the order of K, C, M, and Y along the scanning direction of the carriage 16, but this is not restrictive. Absent.
[0018]
Further, an optical detection means 22 is provided at a position downstream of the carriage 16 in the sheet feeding direction, and the optical detection means 22 is also scanned along with the scanning of the carriage 16. The optical detection unit 22 includes a light projecting unit and a light receiving unit (not shown), outputs light to the paper from the light projecting unit, and receives the light reflected from the paper P by the light receiving unit, thereby being recorded on the paper P. The image density is optically detected.
[0019]
Further, a maintenance unit 24 provided for maintenance of each color print head 18 is disposed outside the recording area in the scanning direction of the carriage 16, and the standby position of the carriage 16 is located at a position where the maintenance unit 24 is engaged. Is set.
[0020]
Next, the configuration of the control system of the color printer 10 according to the embodiment of the present invention will be described with reference to the block diagram of FIG.
[0021]
As shown in FIG. 3, the operation of the color printer 10 is controlled by a microcomputer 26 having a CPU 26, a ROM 28, a RAM 30, and peripheral devices.
[0022]
In the microcomputer 32, a CPU 26, a ROM 28, a RAM 28, an input interface (input I / F) 34 and an output interface (output I / F) 36 are connected to a bus 38. The detection means 22 is connected, and a signal representing the density of the image recorded on the paper P detected by the optical detection means 22 is input to the microcomputer 32.
[0023]
Connected to the output I / F 36 are a driver 42 for driving a transport motor 40 for transporting the paper P and a driver 41 for driving a carriage scanning motor 43 for moving the carriage 16. The conveyance motor 40 and the carriage scanning motor 43 are controlled in accordance with this instruction.
[0024]
Further, each color print head 18 (K print head 18K, C print head 18C, M print head 18M, Y print head 18Y) is connected to the output I / F 36, and the microcomputer 32 outputs from each color print head 18. Ink ejection is controlled.
[0025]
Control of ink ejection from each color print head 18 is performed, for example, by controlling the timing at which ink is ejected from a plurality of ink ejection nozzles provided in each print head 18, thereby recording an image in the scanning direction of the carriage 16. As shown in FIG. 4, the actual use area 44 and the allowable area 46 that are actually used for the plurality of ink ejection nozzles of each print head 18 can be set. By controlling, the image recording position with respect to the conveyance direction of the paper P can be controlled. Further, by correcting the ejection timing and the actual use area 44 at the same time, it is possible to correct the inclination of the print head.
[0026]
Next, detection and adjustment of image shift in the color printer 10 configured as described above will be described with reference to the flowchart of FIG.
[0027]
Here, as shown in FIG. 2, the scanning direction of the carriage 16 is assumed to be the X direction (horizontal direction), the paper transport direction is assumed to be the Y direction (vertical direction), and the inclination with respect to the Y direction is assumed to be tilt.
[0028]
First, in step 100, a K-color parallel bar is printed to perform K-color tilt correction. The K color tilt correction is performed in accordance with the flowchart of FIG.
[0029]
That is, using the nozzles on the upstream side of the K print head 18K, as shown in the upper part of FIG. 7, a plurality of parallel bars 48 that are long in the Y direction are printed along the X direction. The printing interval of the parallel bars 48 is printed with an interval corresponding to the printing length of the parallel bars 48 in the X direction (step 120). At this time, a predetermined number of parallel bars 48 are printed as one block, and printed as parallel bars 48 tilted by 4 dots for each block. Note that the tilt for each block is tilted by 4 dots positively and negatively with the current state as the median value, and has an adjustment width of ± 16 dots as shown in FIG.
[0030]
Subsequently, the paper P is moved in the Y direction so that the nozzle on the downstream side of the K print head 18K is positioned at the position of the parallel bar 48 printed by the nozzle on the upstream side of the K print head 18K (step 122). Then, similarly to the parallel bar 48 printed by the upstream nozzle, it is tilted by 4 dots for each block, and the parallel bar 50 is printed by the upstream nozzle as shown in the lower part of FIG. Printing is performed between the parallel bars 48 (step 124). The density of the parallel bars 48 and 50 printed in this way is detected by the optical detection means 22 mounted on the carriage 16 (step 126), the block with the highest average density is detected, and the tilt amount of the block is set to K. This is set as a temporary tilt amount of the color (step 128).
[0031]
Similarly to step 120, a plurality of parallel bars 48 are printed along the X direction using the upstream nozzle of K color (step 130). At this time, a predetermined number of parallel bars 48 are printed as one block, and printed as parallel bars 48 tilted by one dot for each block. The tilt of each block is such that the provisional tilt amount set in step 128 is set to the median value, and each pixel is tilted positively and negatively by 1 dot, and as shown in FIG. Has been.
[0032]
Subsequently, the sheet P moves in the Y direction so that the nozzle on the downstream side of the K print head 18K is positioned at the position of the parallel bar 48 printed with the temporarily set tilt amount by the nozzle on the upstream side of the K print head 18K. (Step 132). Then, similarly to the parallel bar 48 printed by the upstream nozzle, it is tilted by one dot for each block, and the parallel bar 50 is printed by the downstream nozzle between the parallel bars 48 printed by the upstream nozzle. (Step 134). The density is detected by the optical detection means 22 mounted on the carriage 16 with the parallel bars 48 and 50 printed in this way (step 136), and the block with the highest average density is detected. Set as the color tilt amount. Then, the tilt correction for the K color is performed by correcting the set tilt amount when developing the data. For example, it is possible to perform tilt correction by changing the print timing according to the set tilt amount or by switching print data.
[0033]
As described above, in the K-color tilt correction process, as shown in FIG. 8, the K-color tilt correction is performed by performing the coarse adjustment for every four dots and then performing the fine adjustment for each dot. That is, the number of patterns to be recorded on the paper can be reduced by performing K color tilt correction step by step.
[0034]
Subsequently, when the K color tilt correction is performed in step 100 in FIG. 5, the X direction color registration correction is performed in step 102. The X direction color registration correction is performed according to the flowchart of FIG.
[0035]
That is, the K parallel bars 52K that have been tilt-corrected in step 100 are printed in a plurality of blocks with a predetermined number as one block (step 150), and the nozzle row length is not affected by the tilt of the nozzles on the upstream side of the color print head 18. Each block is printed by printing a color color (any of CMY colors) using a part of the nozzles (printing by repetitive printing by printing the part P and moving the paper P in the Y direction). The parallel bars 52C (or 52M, 52Y) shifted by 4 dots in the X direction are printed between the K parallel bars 52K as shown in FIG. 10 (step 152). Here, the color color parallel bars 52C, 52M, and 52Y are not tilted by repeatedly printing the color color using some nozzles having the nozzle row length not affected by the tilt of the upstream nozzles. As shown in FIG. 10, the K parallel bars and the color parallel bars 52C, 52M, and 52Y are substantially parallel to each other. The shift for each block is shifted by 4 dots positively and negatively with the current state as the median value, and as shown in FIG. 8, the adjustment width is ± 16 dots.
[0036]
Then, the optical detection means 22 mounted on the carriage 16 detects the average density of each block (step 154), the block having the highest average density is detected, and the image shift amount of the block is the temporary registration shift amount. (Step 156). The optical detection unit 22 detects a change in average density caused by a change in the overlapping area due to a difference in shift of each color with respect to the K color.
[0037]
Then, in step 158, it is determined whether or not the temporary setting of each color registration deviation amount has been completed, and the processing of steps 150 to 158 is repeated until the determination is affirmed, and when the determination is affirmed, step 160 is performed. Migrate to
[0038]
When provisional misregistration amounts are set for each color, a plurality of K color parallel bars are printed with a predetermined number of one block as in step 150 (step 160), and the nozzles on the upstream side of the color print head By repeatedly printing color colors using some nozzles having a nozzle row length that is not affected by the tilt in step 1, a parallel bar is printed with a shift of 1 dot for each block (step 162). The shift for each block is shifted by 1 dot in the positive and negative directions with the temporary registration shift amount set in step 156 as the median. As shown in FIG. 8, the adjustment width is ± 4 dots. It is said that.
[0039]
The density of each block is detected by the optical detection means 22 mounted on the carriage 16 (step 164), the block with the highest average density is detected, and the image shift amount of the block is set as the registration shift amount. The Then, the color registration correction in the X direction is performed by correcting the registration registration amount when the data is developed (step 166). For example, it is possible to perform color registration correction by changing the printing timing in accordance with the set registration deviation amount or by switching the printing data.
[0040]
In step 168, it is determined whether or not the registration error correction has been completed for each color, and the processes in steps 160 to 168 are repeated until the determination is affirmed. If the determination is affirmative, the color registration correction process is performed. Ends.
[0041]
As described above, in the X-direction color registration correction process, as shown in FIG. 8, the coarse adjustment is performed for every four dots with reference to the tilt-corrected K color, and then the fine adjustment for each dot is performed. Yes. That is, by performing color registration correction step by step, the number of patterns to be recorded on the paper can be reduced.
[0042]
As described above, since the blocks of the parallel bars of the respective colors are overlapped with the blocks of the parallel bars of the K color, the moire is generated by superimposing the parallel bars of the K color vertical line and the color color whose displacement changes. Thus, the density change can be accurately detected by the optical detection means. At this time, by performing color registration correction based on the tilt-corrected K color, when the density is detected by the optical detection means 22, the K color portion is already saturated, so that the overlapping portion Therefore, the area gradation effect can be obtained purely, and the density change can be detected efficiently. Therefore, the color registration can be accurately corrected by correcting the color registration of each color based on the tilt-corrected K color.
[0043]
By using the K color as a reference, the average density of the recorded pattern increases, and even if the illuminance of the light source is improved, the output of the light receiving element in the optical detection means 22 is not saturated, and the density difference is reduced. Enlargement is possible, density detection accuracy is improved, and light sources having different spectral characteristics are not required. Further, since color registration correction is performed with the same reference (K color with tilt correction) for each color, color registration correction can be performed accurately.
[0044]
In the color registration correction, as shown in FIG. 8, fine adjustment is performed after making coarse adjustment for each color of CMY, but each color (as in a tilt correction process based on K color described later) is performed. You may make it perform rough adjustment and fine adjustment for every CMY).
[0045]
Subsequently, when the X direction color registration correction is performed in step 102 in FIG. 5, in step 104, the tilt correction of each color is performed based on the K color. The tilt correction of each color is performed according to the flowchart of FIG.
[0046]
That is, the K parallel bars 54K tilt-corrected in step 100 are printed as a predetermined number of one block (step 180), and the color parallel bars 54C (or 54M, 54Y) are arranged between the K parallel bars 54K. ) Is printed with a 4-dot tilt for each block (step 182). The tilt for each block is tilted by 4 dots positively and negatively with the current state as the median value, and has an adjustment range of ± 16 dots as shown in FIG. That is, as shown in FIG. 12, the block of color parallel bars 54C (or 54M, 54Y) tilted by 4 dots is printed on the block of K parallel bars 54K that is not tilted. Here, FIG. 12 shows print patterns for K and C, K and M, and K and Y, respectively.
[0047]
Then, the density of each block is detected by the optical detection means 22 mounted on the carriage 16 (step 184), the block with the highest average density is detected, and the tilt amount of the color color of the block is set as a temporary tilt amount. (Step 186). The optical detection unit 22 detects a change in the average density of the blocks caused by a change in the overlapping area of the parallel bars due to a difference in the inclination of each color with respect to the K color.
[0048]
Similarly to step 180, a plurality of K color parallel bars 54K are printed with a predetermined number as one block (step 188), and color color parallel bars 54C (or 54M, 54Y) are arranged between the K color parallel bars 54K. ) Is printed with one dot tilt for each block (step 190). The tilt of each block is such that the provisional tilt amount set in step 186 is set as a median value, and is tilted positively and negatively by 1 dot. As shown in FIG. Has been.
[0049]
Then, the density of each block is detected by the optical detection means 22 mounted on the carriage 16 (step 192), the block having the highest average density is detected, and the color color tilt amount of the block is the color color tilt. Set as a quantity. Then, the color tilt correction is performed by correcting the set amount of tilt when developing the data. For example, it is possible to perform color color tilt correction by changing the print timing in accordance with the set tilt amount or by switching print data.
[0050]
The color color tilt correction is performed by performing the above processing for each color (CMY). However, as in the X-direction color registration correction processing, each color is subjected to coarse adjustment and then each color is finely adjusted. It may be.
[0051]
In this way, in the color color tilt correction in the present embodiment, as shown in FIG. 8, fine adjustment for each dot is performed after coarse adjustment for every four dots with reference to the tilt-corrected K color. By performing the above, the color color tilt correction is performed. That is, the number of patterns to be recorded on the paper P can be reduced by performing the color color tilt correction step by step.
[0052]
By the way, when the tilt correction is performed with a monochromatic pattern as in the prior art, the upstream nozzle and the downstream nozzle are used in the same manner as the K color tilt correction (the flowchart of FIG. 6). As shown in FIG. 13, a single-color pattern is formed for each color. In this case, when the density of each block is detected by the optical detection means 22, as shown in FIG. In this embodiment, as described above, the block of parallel bars of each color is overlaid on the block of parallel bars of K color. Therefore, moire is generated by superimposing the K-color vertical line and the parallel bar of the color color whose inclination changes, and the moire can accurately detect the density change by the optical detection means. At this time, by performing tilt correction of each color color based on the tilt-corrected K color, when the density is detected by the optical detection means 22, the density of the K color portion is already saturated. Since there is no improvement in the density of the overlapping portion, the area gradation effect is obtained purely, and as shown in FIG. 15, the outputs of the light receiving elements are substantially the same for each color, and the density change can be detected efficiently. Therefore, the color color tilt can be corrected accurately. In addition, the horizontal axis pattern block No. shown in FIGS. Is the block No. of the pattern shown in FIGS. Corresponding to
[0053]
By using the K color as a reference, the average density of the recorded pattern increases, and even if the illuminance of the light source is improved, the output of the light receiving element in the optical detection means 22 is not saturated, and the density difference is reduced. Enlargement is possible, density detection accuracy is improved, and light sources having different spectral characteristics are not required. In addition, since the color color tilt correction is performed with the same reference (K color with tilt correction) for each color color, the color color tilt correction can be performed accurately.
[0054]
In this embodiment, since the optical detection means 22 is arranged at a position downstream of the carriage 16 in the paper P feeding direction, the optical detection means 22 performs detection immediately after the pattern is printed. In addition, as shown in FIG. 12, since the position (position on the downstream side in the Y direction) that is most affected by the tilt of each color print head can be detected, the density change can be accurately detected. .
[0055]
Further, when the color pattern is recorded after the K color pattern is recorded, paper feeding is not required, so that the time required for pattern formation can be shortened.
[0056]
Subsequently, when the tilt correction of each color is performed based on the K color in step 104 in FIG. 5, the X-direction reciprocal print correction process is performed in step 106 based on the forward K color. The X-direction reciprocal print correction is performed according to the flowchart of FIG.
[0057]
That is, the parallel bars of K color that have been tilt-corrected in step 100 are printed as a predetermined number of one block on the forward path side of the carriage 16 (step 200), and each color (KCMY) is paralleled between the parallel bars of K color. The bar is shifted by 4 dots for each block and printed on the return path side of the carriage 16 (step 202). That is, as a pattern to be printed, a pattern similar to the X direction color registration correction pattern shown in FIG. 10 is printed. The shift for each block is shifted by 4 dots positively and negatively with the current state as the median value, and as shown in FIG. 8, the adjustment width is ± 16 dots.
[0058]
Then, the density of each block is detected by the optical detection means 22 mounted on the carriage 16 (step 204), the block having the highest average density is detected, and the image shift amount of the block is used as a temporary reciprocal shift amount. It is set (step 206). The optical detection unit 22 detects a change in average density caused by a change in the overlapping area due to a difference in shift of each color with respect to the K color.
[0059]
Similarly to step 200, a predetermined number of parallel bars of K color are printed on the forward side of the carriage 16 with a predetermined number of blocks (step 208), and each color (KCMY) is printed between the parallel bars of K color. The parallel bar is shifted by 1 dot for each block and printed on the return path side of the carriage 16 (step 210). The shift of each block is shifted by 1 dot in positive and negative directions with the reciprocal shift amount set in step 206 as a median, and as shown in FIG. 8, the adjustment width is ± 4 dots. Yes.
[0060]
Then, the density of each block is detected by the optical detection means 22 mounted on the carriage 16 (step 212), the block with the smallest density change is detected, and the reciprocal displacement amount of the block is reciprocated by the reciprocation of the carriage 16. Set as the amount of deviation. Then, the correction of the reciprocal deviation is performed by correcting the amount of the set reciprocal deviation when developing the data. For example, it is possible to correct the reciprocal deviation by changing the print timing according to the set reciprocal deviation amount or replacing the print data.
[0061]
The reciprocal deviation correction is performed by performing the above process for each color (KCMY). However, as in the X direction color registration correction process, each color is subjected to coarse adjustment and then each color is finely adjusted. Also good.
[0062]
As described above, since the blocks of the parallel bars of the respective colors are overlapped with the blocks of the parallel bars of the K color, the moire is generated by superimposing the parallel bars of the K color vertical line and the color color whose displacement is changed. Therefore, the average detection by the optical detection means can be accurately performed.
[0063]
By the way, when the reciprocation correction is performed with a single color pattern as in the prior art, as shown in FIG. 17, the parallel bar blocks printed on the return path are arranged between the parallel bars of the parallel bar blocks printed on the forward path. In this case, when the density is detected by the optical detection means 22, as shown in FIG. 18, the light receiving element output in the optical detection means 22 is formed. However, in the present embodiment, as described above, the parallel bar block of each color is superimposed on the block of the parallel bar of K color. Moire is generated by superimposing the K color vertical lines and the parallel bars of color colors whose displacement changes, and the moire can accurately detect the density change by the optical detection means. At this time, when the density is detected by the optical detection means 22 by performing the reciprocal deviation correction based on the K color that has been tilt corrected and recorded on the forward path, the density of the K color portion is already saturated. Thus, since there is no improvement in the density of the overlapping portion, the area gradation effect is obtained purely, and the density change can be detected efficiently as shown in FIG. Accordingly, by correcting the reciprocal deviation of each color based on the K color that has been tilt-corrected and recorded on the forward path, the reciprocal deviation correction of each color can be performed accurately.
[0064]
By using the K color as a reference, the average density of the recorded pattern increases, and even if the illuminance of the light source is improved, the output of the light receiving element in the optical detection means 22 is saturated as shown in FIG. Therefore, the density difference can be enlarged, the density detection accuracy is improved, and light sources having different spectral characteristics are not required. In addition, since the reciprocal deviation correction is performed with the same reference (K color that has been tilt-corrected and recorded on the outward path) in the forward and backward paths for each color, the reciprocal deviation correction can be performed accurately.
[0065]
When the X-direction reciprocal printing correction is performed based on the forward color K in step 106 in FIG. 5, the Y-direction color registration correction processing is performed based on the K color in step 108. The Y-direction color registration correction is performed according to the flowchart of FIG.
[0066]
That is, a plurality of blocks of K-color parallel bars whose tilt correction has been performed in step 100 is printed with a predetermined number as one block (step 300). In the above processing (steps 100 to 106), blocks composed of parallel bars that are long in the Y direction have been printed. Here, blocks of a plurality of parallel bars to be printed are parallel bars that are long in the X direction. A block consisting of is printed. Then, the color parallel bars are printed by shifting 4 dots in the Y direction for each block between the K parallel bars (step 302). The shift for each block is shifted by 4 dots positively and negatively with the current state as the median value, and as shown in FIG. 8, the adjustment width is ± 16 dots.
[0067]
Then, the density of each block is detected by the optical detection means 22 mounted on the carriage 16 (step 304), the block having the highest average density is detected, and the image shift amount of the block is used as a temporary registration shift amount. It is set (step 306). The optical detection unit 22 detects a change in average density caused by a change in the overlapping area due to a difference in shift of each color with respect to the K color.
[0068]
Similarly to step 300, a plurality of K parallel bars are printed with a predetermined number of blocks as one block (step 308), and the color parallel bars are shifted by 1 dot for each block between the K parallel bars. A parallel bar is printed (step 310). The shift for each block is shifted by 1 dot in positive and negative directions with the registration shift amount set in step 308 as the median, and as shown in FIG. 8, the adjustment width is ± 4 dots. ing.
[0069]
The density of each block is detected by the optical detection means 22 mounted on the carriage 16 (step 312), the block with the highest average density is detected, and the image shift amount of the block is set as the registration shift amount. The Then, the color registration correction in the Y direction is performed by correcting the set registration deviation amount when developing the data (step 314). For example, it is possible to perform color registration correction by selecting a nozzle to be used or replacing print data.
[0070]
The color color tilt correction is performed by performing the above processing for each color (CMY). However, as in the X-direction color registration correction processing, each color is subjected to coarse adjustment and then each color is finely adjusted. It may be.
[0071]
As described above, for the color misregistration correction in the Y direction, the color misregistration correction for each color is performed based on the K color, and the processing of image misalignment detection adjustment is completed.
[0072]
In the image misalignment detection adjustment processing in the above embodiment, the density at the time of recording the parallel bars of K color and color is not mentioned, but the density of each parallel bar may be 100%. Each process may be appropriately different.
[0073]
Further, in each processing of the image misalignment detection processing in the above embodiment, the parallel bar is printed for each block, and the tilt amount, the misalignment amount, etc. are printed differently for each block. Instead of printing, the amount of tilt, the amount of deviation, etc. may be printed differently for each parallel bar.
[0074]
  As described above, according to the present invention, the reference recording headThe upstream side in a given directionRecorded reference parallel bar and reference recording headThe block with the highest average density among a plurality of blocks with different inclinations composed of the reference parallel bar recorded on the downstream side in the predetermined directionOn the basis of the,StandardRecording headNotationSince the recording position is adjusted, images recorded by all recording headsStandardRecording headToCan be put together,StandardRecording headNotationThere is an effect that the recording position can be corrected accurately.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating a schematic configuration of a color printer according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an arrangement of printer heads for each color.
FIG. 3 is a block diagram showing a control system of the color printer according to the embodiment of the present invention.
FIG. 4 is a diagram illustrating a recording area of a print head.
FIG. 5 is a flowchart showing image misalignment detection adjustment;
FIG. 6 is a flowchart showing K color tilt correction processing;
FIG. 7 is a diagram for explaining K color tilt correction;
FIG. 8 is a diagram showing a series of flows for detecting and adjusting image misalignment.
FIG. 9 is a flowchart illustrating an X direction color registration correction process;
FIG. 10 is a diagram illustrating an X-direction color registration correction pattern.
FIG. 11 is a flowchart illustrating a color tilt correction process.
FIG. 12 is a diagram illustrating a color tilt correction pattern.
FIG. 13 is a diagram illustrating a conventional color tilt correction pattern.
FIG. 14 is a diagram showing a detection output of a conventional color tilt correction pattern by an optical detection means.
FIG. 15 is a diagram showing a detection output of a color tilt correction pattern in the present embodiment by an optical detection means.
FIG. 16 is a flowchart showing a reciprocal deviation correction process.
FIG. 17 is a diagram showing a conventional reciprocal deviation correction pattern.
FIG. 18 is a diagram showing a detection output of a conventional pattern for correcting reciprocal deviation by an optical detection means.
FIG. 19 is a diagram showing a detection output of a reciprocal deviation correction pattern in the present embodiment by an optical detection means.
20 is a diagram showing a detection output of a pattern for correction of reciprocal deviation in the present embodiment by an optical detection unit under an illuminance improvement condition (illuminance approximately twice as large as that in FIG. 19).
FIG. 21 is a flowchart showing Y-direction color registration correction processing;
[Explanation of symbols]
10 Color printer
18 Print head
18K K print head
18C C print head
18M M print head
18Y Y print head

Claims (5)

Each provided a plurality of nozzles each arranged along a line with a predetermined direction intersecting the scanning direction and the scanning direction, that records a color image by reciprocating scanning over the recording medium in the scanning direction, the color of each recording Is an image recording position adjusting method for adjusting each recording position of a plurality of different recording heads,
Among the plurality of recording heads, a recording head having a predetermined color is set as a reference recording head, and a plurality of nozzles positioned upstream of the reference recording head in the predetermined direction are used to place the recording head on the recording medium in the predetermined direction. A block consisting of a plurality of first reference parallel bars having the same inclination angle with respect to each other, and recording a plurality of blocks along the predetermined direction so that the inclination angles of the first reference parallel bars of each block are different,
A second angle at which the inclination angle is the same as the inclination angle of the first reference parallel bar in each block on the recording medium using a plurality of nozzles positioned downstream of the reference recording head in the predetermined direction. Record a reference parallel bar between the first reference parallel bars of each block;
The average density of each block including the first reference parallel bar and the second reference parallel bar is detected, and the inclination angle of the bar having the highest average density is set as the inclination amount of the reference recording head. Thus , the image recording position adjusting method is characterized in that the recording position of the reference recording head is adjusted.   2. The image recording position adjusting method according to claim 1, wherein the reference recording head is a black recording head for recording a black image. After adjusting the recording position of the reference recording head, a block composed of a plurality of third reference parallel bars arranged in the scanning direction on the recording medium using the reference recording head, A plurality of blocks are recorded along the predetermined direction so that the position of the reference parallel bar is shifted by predetermined dots in the scanning direction,
Recording a first parallel bar on the recording medium using a recording head different from the reference recording head between the plurality of third reference parallel bars of each block;
Detecting an average density of each block including the third reference parallel bar and the first parallel bar, and setting a dot shift amount of the block having the highest average density as a correction amount of the other recording head; 3. The image recording position adjusting method according to claim 1, wherein the recording position of a recording head different from the reference recording head is adjusted. After adjusting the recording position of the reference recording head, the reference recording head is used to record a plurality of reference parallel bars on the recording medium during forward scanning or backward scanning,
Using the reference recording head or a recording head different from the reference recording head, a plurality of parallel bars are recorded on the recording medium during forward and backward scanning,
The image recording position adjustment according to claim 1, wherein the recording positions of the plurality of recording heads during forward and backward scanning are adjusted based on a positional relationship between the reference parallel bar and the parallel bar. Method. After adjusting the recording positions of the recording heads different from the reference recording head and the reference recording head, the reference recording head is used to record a plurality of reference parallel bars on the recording medium during forward scanning or backward scanning. ,
Using the reference recording head or a recording head different from the reference recording head, a plurality of parallel bars are recorded on the recording medium during forward and backward scanning,
4. The image recording position adjusting method according to claim 3, wherein the recording positions of the plurality of recording heads during forward and backward scanning are adjusted based on a positional relationship between the reference parallel bar and the parallel bar.

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